Hydraulic-pneumatic draft gear



Nov. 21, 1961 J. 1.. GIBSON 3,009,584

HYDRAULIC-PNEUMATIC DRAFT GEAR Filed Sept. 8, 1959 FIG. 6. JAMES L. GIBSON INVENTOR.

BY [E v A T TORNE Y United States Patent 3,009,584 HYDRAULItI-PNEUMATIC DRAFT GEAR James L. Gibson, P.0. Box 761, Fort Worth, Tex. Filed Sept. 8, 1959, Ser. No. 838,657 4 Claims. (Cl. 213-43) This invention relates to railroad cars and has reference to an improved draft gear for absorbing the shock of impact between cars during coupling and switching operations. This application is a continuation in part of my copending application, Ser. No. 539,375, filed October 10, 1955, now Patent No. 2,909,291, and is particularly directed to the combined hydraulic and pneumatic features shown and described therein.

An object of the invention is to provide hydraulicpneumatic means in draft gears for absorbing shock loads, yet having very little recoil action.

A particular object is to provide intercommunication between hydraulic-pneumatic draft gears at opposite ends of a railway car in a manner whereby both coact to provide a cushioning effect, yet may be selectively extended to eliminate slack while the train is in motion.

Another object is to provide draft gears at the ends of a railroad car and wherein the bumping of one draft gear will cause the other to extend beyond in position to absorb the maximum shock of the next car coupling.

Another object is to provide a draft gear which has sufficient cushioning effect in both buff and draft even though subjected to jerking starts.

A further object is to provide effective cushioning when draft gears at the ends of a car are forced inwardly at the same time.

Another object is to provide hydraulic-pneumatic draft gears which tend to return to normal positions after impact.

A further object is to provide an improved draft gear system having conventional couplings, and whereby a car including the improvements may be integrated in trains wherein some of the cars have standard draft gears.

These and other objects will become apparent from the following description and accompanying drawing, wherein:

FIGURE 1 is a longitudinal broken sectional view of a draft gear embodying the features of the invention.

FIGURE 2 is a broken top plan view, shown partly in broken section, of a draft gear as illustrated in FIGURE 1 and additionally showing the car sill and coupling.

FIGURE 3 is a transverse sectional view taken on line 3-3 of FIGURE 2. and showing the cylinder and piston of the invention mounted between channel beams of the sill.

FIGURE 4 is a diagrammatic view of a coupling system in a railroad car and embodying the preferred form of the invention.

FIGURE 5 is a diagrammatic view similar to FIGURE 4, but embodying an alternate form of the invention.

FIGURE 6 is a vertical sectional View similar to FIG- URE 1, but illustrating the alternate form of the invention referred to in connection with FIGURE 5.

Both illustrated forms of the invention are designed for operation between channel beams 10 which comprise the sill of a railroad car and at the ends thereof. Transverse buffer plates 11 are secured across the upper ends of the channel beams 11 and conventional draw bars 12 extend outwardly thereof in the usual manner, and which draw bars have couplings 13 on their extending ends. The draw bar 12 may be of the spring loaded friction type if so desired.

Referring now to the form of the invention illustrated in FIGURES 1 through 4, there is a cylinder 14 mounted between the channel beams 10 relatively near each end PatentedNov. 21, 1961 of sill but spaced therefrom a distance to accommodate draw bar connections and means limiting draw bar movement hereinafter described, and each cylinder has a piston 15, a piston rod 16 extending toward the drawbar 12 and connected therewith by means of a U-shaped connection 17 and pin 18 therethrough. The end of the cylinder 14 through which the piston rod 16 extends is provided with a cylinder head 19 and packing gland 20. Within the cylinder head i19', and preferably at the bottom thereof, there is an air exhaust port 21 which communicates with the atmosphere through a threaded fitting 22, and the inner end of which fitting seats a check valve 23 having a bleeder port 24 therethrough. The check valve 23 may be spring loaded as shown and described in my referred to copending application. The cylinder 14 is secured to opposing surfaces of the channel beams 10 by means of integral brackets 25 as shown in FIGURES 2 and 3.

The inner end of the cylinder 14 is provided with a circular partition 26 having an axial opening 27 therethrough. The end of the piston rod 16 opposite the draw bar 12 has a tapered projection 28 for gradually closing the partition opening 27 when the piston 15 moves to that end of the cylinder.

A cylindrical reservoir 29 is secured to the partition 26 on the side thereof opposite the cylinder 14, and which reservoir has a free floating piston 30 therein. There is a flapper check valve 31 mounted on the partition 26 and within the reservoir 29 for closing that end of the partitions axial opening 27. The check valve 31 has a bleeder port 32 therethrough, the purpose of which will be come apparent in the description of operation to follow. Oil or other hydraulic fluid is provided in the cylinder 14 and reservoir 29 in the ends thereof including the partition 26.

Referring now to FIGURES l and 2, there is a transverse key 33 extending through the draw bar 12 at the pin 18, and the ends of which key extend into horizontal longitudinal key slots 34 in the sill channel beams 10. The key slots 34 are reinforced by integral inwardly projecting draft gear frames 35 therearound. Guides 36 in the form of elongate collars may be secured, as by riveting, on the key 33 for sliding contact with the opposing surfaces of the draft frames 35.

Referring now to FIGURES 1 and 4, the ends of the reservoirs 29, opposite the partitions 26, there are closures 37 having fittings 38 for connecting an air line 39, thus providing communication between the air ends of the two reservoirs. A controlled air supply line 40 is connected with the connecting line 39 intermediate the ends thereof.

When switching and connecting cars, the supply line 40 is closed with sufiicient air in the reservoirs 29 to at least partially extend the draw bars 12. Impact at one end of the car causes the piston 15 to move inwardly and to cause the tapered projection 28 to enter and gradually close the partition opening 27. At the same time, oil passing through the opening 27 moves the free floating piston 30 and partially displaces the air in the reservoir 29. The displaced air is transferred to the other reservoir through the connecting line 39, and which action moves the free floating piston 30 in the second reservoir with the result that the cylinder piston 15 and attached draw bar 12 are moved outwardly of the end of the car. The last referred to action is dampened by reason of oil having to pass through the flapper bleeder port 32, and displaced air in the cylinder 14 passing through the bleeder port 24 in the cylinder check valve 23. 'It is to be understood that when the impact load is momentary, the compressed air within the reservoir 29 tends to return the floating piston 30 to its normal intermediate position, and which action has a cushioning effect on the cylinder piston 15.

When starting a train air is slowly displaced from the cylinder 14 through the check valve bleeder port 24, and

at the same time oil enters the cylinder through the fiapper check valve bleeder port 32. When extended, the keys 33 engage the outer ends of the key slots 34, and which position may be selectively maintained by air pressure introduced through the supply line 40. It is to be understood that simultaneous impact loads at each end of a car are cushioned by the displacement of oil in the cylinders 14 and the compression of air in the reservoirs 29.

The form of the invention illustrated in FIGURES 5 and 6 is substantially identical with the foregoing except that the reservoirs 29 are not directly connected with the cylinders 14-. Also, the free floating piston 30 is eliminated. The axial opening 27' in the cylinder partition 26 is provided with a fitting 41, a hydraulic line 42 and fitting 43 in the bottom of each reservoir 29, and inwardly of the last referred to fitting there is a flapper type check valve 31' having a bleeder port 32' therethrough. The connecting line 39 between reservoirs 29 enter the tops of the latter. The operation of the last described form of the invention is in accordance with the first form of the invention except that oil is entrained in and displaced from the bottoms of the reservoirs 29, all other operations being the same.

The invention is not limited to the exemplary construction herein shown and described, but may be made in various ways within the scope of the appended claims.

What is claimed is:

1. In a draft gear for a railway car having a pair of parallel sill members extending lengthwise of the bed thereof, a draw bar positioned between the end portions of said sill members at each end thereof and extending outwardly therefrom, a cylinder mounted between said sill members inwardly of each said draw bar and in longitudinal alignment therewith, a piston within each said cylinder, a piston rod connecting each said draw bar with each said piston, an oil reservoir for coaction with each said cylinder and partly filled with oil, the portion of said reservoir not filled with oil being filled with air, means communicating the end of said cylinder opposite said draw bar with said reservoir, oil in the last said end of each said cylinder and said means communicating the latter with each said reservoir, means separating air and oil in said reservoirs, and a connecting line between each said reservoir communicating air therebetween.

2. In a draft gear for a railway car as defined in claim 1, the construction including a check valve in each said means communicating each said cylinder with each said reservoir, and bleeder means through each said check valve, said check valves being arranged to retard movement of said pistons in the direction of said draw bars.

3. In a draft gear for a railway car as defined in claim 1, the construction including a controlled air supply line connected with said connecting line between said reservoirs.

4. In a draft gear for a railway car as defined in claim 1, the construction including opposing longitudinal slots in said sill members near the ends thereof, and a key through each said draw bar and extending into opposing said slots, the width of said keys being less than the length of said s ots.

References Qited in the file of this patent UNITED STATES PATENTS 781,716 Dennis Feb. 7, 1905 1,351,141 Thompson Aug. 31, 1920 1,772,387 Dickerson Aug. 5, 1930 1,955,349 Stevens Apr. 17, 1934 

